2004 ltz400 in ireland mods are,full yoshimura systum,with no db killer,protek lid on airbox with twinair foam filter...bike is holding back lott ..i got guy to jet it back last year with a dyno jet kit i got...he used 150 main jet and 3rd clip on needle,pilot standerd 22.5 and air screw mixture screw is 2.5 turns out..
bike pops on deceleration and is flat spots .. and my plug is black sutty ,i fitted new plug and was black in one start up...he has my jet kit and probely gone now so im looking for opinions on what i should get in single jets im bout 350 feet over sea level 400 in rding places give or take a bitt...
so iff ye could help me out all advise welcome
pilot jet size ?___________
main jet ?_____________
needle clip to what position ?_____________
how many turns out air mixture screw?_____________

 

Bump need help here its actually a 156 main thats in it and its 4 turns out with stock pilot even do guy that done it has writen its a 60 pilot please help people

 

That is really weird and shouldn't happen. Is your engine a carburetor able to take that type of jet kit?